A. Technical Field
The present invention relates to a production process and a production apparatus for a resin particle to provide a fine resin particle in a state where its particle size is uniform, and further, the invention relates to a product of the resin particle.
B. Background Art
In recent years, a resin particle is widely used in various fields. Specific examples of the use of the resin particle are as follows: clearance holding materials (spacers for liquid crystal display elements), slipping agents, functional carriers, toners, and functional fillers that control the fluidity or gloss properties of paints. As to the resin particle as utilized for these uses, its particle diameter needs to be controlled depending on the uses.
An example of methods to easily obtain the resin particle is a suspension polymerization method, in which a dispersing phase component such as a polymerizable monomer composition insoluble in a continuous phase component such as water is dispersed in the form of a liquid drop into the continuous phase component, and the liquid drop is then polymerized, thus obtaining a resin particle.
The conventional suspension polymerization method has a problem in that the particle diameter distribution of the liquid drop as dispersed in the continuous phase component is broad.
For example, the above-mentioned various uses often need a fine resin particle with an average particle diameter of less than 10 .mu.m. However, there is a problem in that: where the particle diameter is lessened simply by mechanical operation, the distribution of the applied force in the system tends to be non-uniform, and therefore, the formation of fine particles is greatly increased, but particles of which the dispersing is only slowly promoted also remain and large-sized particles are allowed to also be present, so the resultant particle diameter distribution is broad.
Conventionally, there is also a process in which: a resin is dissolved into a solvent, the resultant solution is dispersed into a water base continuous phase, and the solvent is volatilized, thus obtaining a resin particle; or a process in which: a resin as melted by heating is dispersed into a heated water base continuous phase to regulate the particle diameter, and the water base continuous phase is then cooled, thus forming a resin particle. However, it is similarly indicated that there is a problem in that the resultant particle diameter distribution is broad.